The efficacy of three plants used in homeopathy to treat acute tonsillitis was evaluated. A fixed combination of three plant substances (Phytolacca americana, Guajacum officinale, Capsicum annuum) was used in either solid (tablet) or liquid (drop) formulation: 107 patients were treated and no antibiotics were used. The objective and subjective symptoms of acute tonsillitis were noted. A significant decrease in symptoms was observed as early as 2.5 days after treatment startup; no serious adverse effects were reported. It was concluded that acute tonsillitis can be treated with a homeopathic remedy characterized by its immunomodulatory, analgesic, and anti-inflammatory properties.