Cold and Flu: When to See a Doctor and Home Remedies That Work
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The common cold and influenza are both respiratory illnesses, but they are caused by different viruses and tend to behave quite differently. Telling them apart matters because the treatment approach, the potential for complications, and the urgency of medical care can all differ.
A cold typically comes on gradually. Symptoms tend to start with a sore or scratchy throat, followed by a runny or blocked nose, sneezing, and a mild cough. Fever is uncommon in adults with a cold, and while the illness can feel unpleasant, most people are able to continue with their daily activities in some reduced capacity. Colds are most often caused by rhinoviruses and usually resolve within seven to ten days without medical treatment.
Influenza, on the other hand, tends to hit suddenly and hard. The hallmarks are a high fever (often 38 degrees Celsius or above), severe body aches, headache, fatigue, and a dry cough. Sore throat and nasal congestion can occur with the flu, but the dominant features are the systemic symptoms: that overwhelming feeling of being knocked flat. Influenza is caused by influenza A or B viruses and can last one to two weeks, with fatigue sometimes lingering for several weeks after the acute illness has passed.
Healthdirect Australia notes that one useful rule of thumb is to consider whether the symptoms are mainly above the neck (suggesting a cold) or affecting the whole body (suggesting the flu). This is not a diagnostic test, but it can help guide early thinking about what to expect and when to seek medical advice.
It is worth noting that other respiratory infections, including COVID-19 and RSV (respiratory syncytial virus), can present with overlapping symptoms. If there is any uncertainty about the cause of symptoms, speaking with a GP can help clarify the picture and guide appropriate testing or treatment.
Understanding what different symptoms signal can help patients make better decisions about self-care and when to seek medical attention.
Runny or stuffy nose is one of the most common cold symptoms. It is the body's response to viral infection in the nasal passages. The mucus helps trap and flush out the virus. Clear mucus is typical early on; thicker, yellow, or green mucus later in the illness is a normal part of the immune response and does not automatically indicate a bacterial infection.
Sore throat is common at the onset of a cold and occasionally with the flu. Most sore throats associated with viral upper respiratory infections resolve on their own within a few days. A sore throat that is very severe, accompanied by high fever, or that lasts longer than a week may warrant a GP review to rule out bacterial causes such as streptococcal infection.
Cough can accompany both colds and influenza. With a cold, it tends to be mild and productive. With the flu, the cough is often dry and persistent. A cough that lasts beyond three weeks, produces blood-stained sputum, or is accompanied by shortness of breath should prompt a medical consultation.
Fever is uncommon with a straightforward cold but is a hallmark of influenza. A temperature above 38 degrees Celsius, particularly when combined with body aches and fatigue, is more consistent with the flu. Fever that lasts longer than three to four days, or that resolves and then returns, may suggest a secondary infection and should be assessed by a GP.
Body aches and fatigue are the symptoms that most clearly differentiate influenza from a cold. The muscle pain and profound tiredness that come with the flu are caused by the body's inflammatory response to the virus. These symptoms can be debilitating and are a key reason why influenza carries a higher risk of complications than the common cold.
Headache is more common with the flu than with a cold. Sinus pressure from nasal congestion can cause headache in both conditions, but the intense, generalised headache typical of influenza is usually part of the broader systemic response.
There is no shortage of cold and flu remedies circulating online, from vitamin megadoses to herbal teas to old family recipes. Some of these have genuine evidence behind them, while others offer little more than comfort. Here is what the research says about the most commonly discussed options.
Rest and hydration
This is the most straightforward and well-supported recommendation. The body needs energy to fight infection, and rest allows the immune system to do its work. Adequate fluid intake helps keep mucus thin and easier to clear, prevents dehydration (especially important when fever is present), and supports overall recovery. Water, clear broths, and warm drinks are all appropriate choices. The World Health Organization and Healthdirect Australia both emphasise rest and fluids as the foundation of managing mild respiratory illness at home.
Honey
Honey has been shown in several studies, including a Cochrane systematic review, to be as effective as some over-the-counter cough suppressants for reducing cough frequency and severity in adults and children over the age of one. A teaspoon of honey, taken straight or mixed into warm water or tea, may help soothe a sore throat and reduce night-time coughing. Honey should never be given to infants under twelve months of age due to the risk of infant botulism.
Saline nasal irrigation
Rinsing the nasal passages with saline solution (using a neti pot, squeeze bottle, or saline spray) can help relieve nasal congestion and remove mucus. A Cochrane review found that nasal saline irrigation may provide symptomatic relief for acute upper respiratory infections. It is a low-risk intervention that can be repeated several times a day. Use sterile or previously boiled and cooled water to prepare the solution.
Steam inhalation
Breathing in warm, moist air from a bowl of hot water or during a warm shower can temporarily relieve nasal congestion. While the evidence for steam inhalation as a treatment is modest, many patients find it provides short-term comfort. Care should be taken to avoid burns, particularly with children.
Zinc lozenges
Some studies suggest that zinc lozenges, when started within the first 24 hours of cold symptoms, may reduce the duration of illness by approximately one to two days. The evidence is mixed, and the Cochrane Collaboration notes that the quality of available studies varies. Side effects can include nausea and an unpleasant taste. Zinc nasal sprays should be avoided, as they have been associated with loss of smell.
Vitamin C
The role of vitamin C in cold prevention and treatment has been studied extensively. A Cochrane review of the evidence concluded that regular vitamin C supplementation does not prevent colds in the general population, but may slightly reduce the duration and severity of symptoms in people who are already taking it regularly. Taking large doses of vitamin C after symptoms have already started does not appear to offer meaningful benefit for most people.
Chicken soup
There is some evidence, including a frequently cited study from the journal Chest, that chicken soup may have mild anti-inflammatory properties and can help with hydration and warmth. While it is not a clinical treatment, warm soup with vegetables and broth is a reasonable part of a comfort-care approach during illness.
Australian pharmacies offer a wide range of over-the-counter cold and flu treatments. Understanding what each type does can help patients choose wisely and avoid spending money on products that are unlikely to help.
Paracetamol and ibuprofen
These are the two most commonly recommended pain relievers and fever reducers for cold and flu symptoms. Paracetamol is generally well tolerated and effective for reducing fever, headache, and body aches. Ibuprofen offers similar benefits along with anti-inflammatory action, which can help with sore throat and sinus pain. NPS MedicineWise recommends using the lowest effective dose for the shortest time needed. Patients should be aware that many combination cold and flu products already contain paracetamol, and taking additional paracetamol on top of these can lead to accidental overdose.
Decongestants
Oral decongestants such as pseudoephedrine and topical nasal decongestants such as oxymetazoline can help relieve nasal congestion. Oral decongestants may raise blood pressure and are not suitable for everyone, including people with hypertension or certain heart conditions. Topical nasal decongestant sprays should not be used for more than three to five consecutive days, as prolonged use can lead to rebound congestion. These products are available from the pharmacist, often behind the counter.
Cough suppressants
Dextromethorphan is the most common cough suppressant found in over-the-counter products. The evidence for its effectiveness in reducing cough is limited. The RACGP notes that most coughs associated with viral upper respiratory infections are self-limiting and do not require specific treatment. For a dry, persistent cough that is disrupting sleep, a cough suppressant may provide modest relief, but it is not a first-line recommendation for everyone.
Antihistamines
Older (first-generation) antihistamines such as chlorpheniramine or promethazine may help dry up a runny nose and improve sleep, but they cause drowsiness and are not suitable for use during the day if driving or operating machinery. Newer (second-generation) antihistamines have little effect on cold symptoms and are mainly useful for allergy-related congestion.
Combination products
Many cold and flu products combine paracetamol, a decongestant, and sometimes a cough suppressant or antihistamine into a single tablet or liquid. These can be convenient but carry a risk of double-dosing on paracetamol if patients are not careful. NPS MedicineWise recommends treating specific symptoms individually rather than using combination products, as this allows better control over what is being taken and in what dose.
Antibiotics
Antibiotics do not work against viruses and are not effective for treating the common cold or influenza. Prescribing antibiotics for viral infections contributes to antibiotic resistance, which the World Health Organization has identified as one of the biggest threats to global health. Antibiotics may be appropriate if a secondary bacterial infection develops, such as bacterial sinusitis or pneumonia, but this should be determined by a GP.
Most colds and many cases of influenza can be managed at home with rest, fluids, and over-the-counter symptom relief. However, there are situations where medical attention is important and, in some cases, urgent.
Red flags that warrant prompt medical attention
- Difficulty breathing or shortness of breath
- Chest pain or pressure
- Persistent vomiting or inability to keep fluids down
- Confusion, dizziness, or altered consciousness
- Fever above 38.5 degrees Celsius that lasts more than three days, or fever that resolves and then returns
- Symptoms that improve and then suddenly worsen
- A cough that produces blood-stained sputum
- Severe or worsening sore throat with difficulty swallowing
Any of these symptoms should prompt a GP consultation or, in the case of severe breathing difficulty or altered consciousness, a call to 000 or a visit to the nearest emergency department.
Vulnerable populations
Certain groups face a higher risk of serious complications from influenza and should seek medical advice early in the course of illness, even if symptoms initially seem mild. According to the Australian Government Department of Health, these groups include:
- Adults aged 65 and over — the immune system becomes less effective with age, increasing the risk of pneumonia and other complications
- Children under five, particularly those under two years of age
- Pregnant women — influenza can pose risks to both the mother and the developing baby
- People with chronic conditions such as asthma, diabetes, heart disease, or chronic kidney disease
- People with weakened immune systems, including those undergoing cancer treatment or taking immunosuppressive medications
- Aboriginal and Torres Strait Islander people, who experience higher rates of influenza-related complications
For patients in these groups, antiviral medications such as oseltamivir (Tamiflu) can be most effective when started within 48 hours of symptom onset. This makes early access to a GP consultation particularly important during flu season.
Need a doctor today?
The single most effective way to reduce the risk of influenza and its complications is annual vaccination. The influenza vaccine is updated each year to match the circulating strains and is recommended by the RACGP for all Australians aged six months and over.
Under the National Immunisation Program, the flu vaccine is available free of charge for people in high-risk groups, including adults aged 65 and over, pregnant women, Aboriginal and Torres Strait Islander people aged six months and over, and individuals with certain chronic medical conditions. For everyone else, the vaccine is available at a relatively low cost through GPs and pharmacies.
The flu vaccine does not guarantee complete protection. Healthdirect Australia notes that vaccine effectiveness varies from year to year, typically ranging from 40 to 60 per cent. However, even when the vaccine does not prevent infection entirely, vaccinated individuals who do contract the flu tend to experience milder symptoms, shorter illness duration, and a lower risk of serious complications including hospitalisation and death.
It is not possible to get the flu from the flu vaccine. The injectable vaccine used in Australia contains inactivated virus components and cannot cause influenza infection. Some people experience mild side effects such as soreness at the injection site, low-grade fever, or fatigue for a day or two after vaccination. These are normal immune responses and resolve quickly.
The optimal time for flu vaccination in Australia is typically between April and June, ahead of the peak flu season. However, it is not too late to be vaccinated later in the season, as influenza can circulate well into spring. A GP can advise on the most appropriate timing and vaccine formulation based on individual circumstances.
When cold or flu symptoms strike, getting timely medical advice should not depend on whether a local clinic has an available appointment this week. Abby Health is Australia's largest online-first clinic, providing GP consultations seven days a week, 365 days a year.
For patients dealing with cold or flu symptoms, a consultation with an Abby Health GP can help in several practical ways:
Assessment and diagnosis. A GP can evaluate symptoms, differentiate between a cold and the flu, and identify any signs of complications. This is especially important for patients in vulnerable populations, where early medical intervention may significantly reduce the risk of serious outcomes.
Prescriptions during the consultation. If clinically appropriate, a GP can prescribe antiviral medication such as oseltamivir, which may reduce the severity and duration of influenza when started early. Prescriptions for other medications, including antibiotics for confirmed secondary bacterial infections, can also be issued during the consultation and sent directly to a preferred pharmacy.
Medical certificates. For patients who need time off work or study to recover, medical certificates can be issued during the consultation without the need for an in-person visit.
Ongoing care with a doctor who knows the patient. One of the things that sets Abby Health apart is continuity. With a 71% rebook rate, three in four patients see the same doctor again. That means a GP who already understands a patient's medical history, existing conditions, and medication regimen. Abby AI, the clinic's medical AI, supports every consultation by surfacing relevant patient history, symptoms, and risk signals so clinicians start informed. This is especially valuable for patients managing chronic conditions that can increase the risk of flu-related complications.
Bulk billed for eligible patients with a valid Medicare card. Cost should not be a barrier to getting medical advice when symptoms are worsening. Eligible patients can access Abby Health consultations at no out-of-pocket cost.
Booking a consultation is straightforward. Patients can schedule an appointment at a time that suits them, or join the First Available queue for the next available GP. Either way, care is accessible from home, which is often exactly where a person with cold or flu symptoms should be.
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