No. Homoeopathy medicines if prescribed according to the principles cannot have any side effect. Instead it will give the patient some side benefits. For an e.g. if a female patient comes with chronic headache and when medicine is prescribed based on the totality of the sufferings her other complaints like menstrual irregularities, hair fall, skin rashes etc also disappears. Here according to principles means the dosage. Some times too frequent repetition of some mother tinctures or a low potency medicine for a prolonged time will have some adverse effect.