Aconitum napellus: A flu that comes on suddenly and intensely—with fever, anxiety, constricted pupils, and strong thirst—is likely to respond to this remedy. The person may feel fearful or agitated, and the fever can alternate with chills. Symptoms are often worst around midnight. Exposure to cold wind or a shock of some kind often precedes the illness.

Apis mellifica: This remedy may be helpful if a person has dry fever that alternates with sweating, facial flushing, and a very sore throat with swollen tonsils. Pain may extend to the ears, and the eyelids may be swollen. Exposure to cool air and cold applications may bring relief. Despite the fever, thirst usually is low. The person can be very irritable, disliking interference.

Arsenicum album: A person who needs this remedy during flu feels chilly and exhausted, along with an anxious restlessness. The person may be thirsty, but often only takes small sips. If the digestive system is involved, nausea with burning pain, or vomiting and acrid diarrhoea may occur. If the flu is respiratory, a watery, runny nose with sneezing paroxysms and a dry or wheezing cough are often seen. The person’s head usually feels hot, while the rest of the body is chilly.

Belladonna: Sudden, intense symptoms — including fever, red face, hot skin, and extreme sensitivity to light and jarring — suggest a need for this remedy. The person may have a very red sore throat, a pounding headache, a nagging cough, or other throbbing and inflammatory symptoms. Despite high fever, the person’s hands and feet may feel cold, or chills and heat may alternate.

Bryonia: When a person is very grumpy and feels miserable with the flu, wanting only to lie still and be left alone, this remedy is likely to be useful. Headache, muscle aches, and cough or stomach pain may be the major symptoms. Everything feels worse from even the slightest motion. The person’s mouth usually is dry, with a thirst for long cold drinks.

Eupatorium perforliatum: Flu with deep pain occurring in the legs or back (“as if the bones would break”) often responds to this remedy. Pain may be felt in the eyeballs, with a heavy sensation in the head. Illness often begins with chills and thirst, followed by high fever. Chills may be felt the back and legs, and the aching in the bones is worse from motion. The person feels “wiped out” and miserable.

Ferrum phosphoricum: This remedy may be helpful during flu with fever, headache, rosy cheeks, and a feeling of weariness. Sensitive eyes, a short hard cough, strong thirst, and vomiting after eating are other indications. This remedy is often helpful in early stages of flu or fever, even if symptoms are not especially clear.

Gelsemium: Symptoms of fatigue and achiness that come on gradually, increasing over several days, may indicate a need for this remedy. The face feels heavy, with droopy eyes and aching. A headache may begin at the back of the neck and skull, and the person may feel chills and heat running up and down the spine. Anxiety, trembling, dizziness, perspiration, and moderate fever are other indications for Gelsemium.

Nux vomica: When this remedy is indicated in influenza, the person may have have high fever, violent chills, strong nausea and cramping in the digestive tract (or a painful cough and constricted breathing if the flu is respiratory). Headache usually occurs, along with oversensitivity to sound, bright light, and odours. A person who needs Nux vomica is often very irritable, feeling worse from exertion and worse from being cold in any way.

Oscillococcinum® (also called Anas barbariae): Oscillococcinum is the brand name of a remedy widely used in the United States and Europe for treating flu symptoms. Research suggests that it has strong antiviral effects.

Phosphorus: When this remedy is needed during flu, the person has a fever with an easily-flushing face, and feels very weak and dizzy. Headache, hoarseness, sore throat, and cough are likely. If the focus is digestive, stomach pain and nausea or vomiting usually occur. A person who needs this remedy often has a strong anxiety, wanting others to be around to offer company and reassurance. Strong thirst, with a tendency to vomit when liquids warm up in the stomach, is a strong indication for Phosphorus.

Rhus toxicodendron: A person who needs this remedy during flu feels extremely restless. Fever is accompanied by bone and muscle aches. Sore throat, red tongue, a teasing cough, and nausea and bloating are other likely symptoms. Soreness and stiffness may be felt all over, with improvement from hot showers or from getting up and pacing. A person who needs Rhus tox usually feels worse when waking up, after lying in bed, or from keeping still too long. Symptoms are relieved by rubbing and stretching, but especially warmth and movement.

Sulphur: This remedy may be useful if a flu is very long-lasting or has some lingering symptoms—often after people have neglected to take good care of themselves. Symptoms, either digestive or respiratory, will often have a hot or burning quality. The person may feel hot and sweaty, with low fever and reddish mucous membranes. Heat aggravates the symptoms, and the person often feels worse after bathing.

(See also Homoeopathic Remedies for Infection, Common Cold, and Cough.)