See below for classic descriptions of some common remedies. Consult the Materia Medica to differentiate further.
ACONITUM—Sudden onset after exposure to cold, dry winds, being chilled. Great agitation.
ARSENICUM ALBUM—With chills, vomiting and diarrhea, and anxiety causing restlessness. Desires warmth, hot drinks, thirsty for small sips often.
BELLADONNA—Sudden, violent onset with flushed face, hot skin, violent headache. Thirstless.
BRYONIA—Slow developing, aching in every muscle, worse for any type of movement. Strong thirst for large amounts of liquids infrequently. Desire cool applications and air.
GELSEMIUM—Classic flu remedy with dull, lethargic feeling, aching in the limbs, shivers up and down the back. Dull, heavy headache, thirstless.
NUX VOMICA—Irritable, snappish, and sensitive to any draughts. Extreme chilliness, even with fever cold air aggravates. Sensitive to light and sound, worse in the morning. May have disturbed sleep due to backache.
RHUS TOXICODENDRON—Restless flu with achiness in the limbs, chilliness. Worse for cold and damp and is better for continued motion.