Acute pharyngitis commonly causes sore throat and pain on swallowing. This multicenter trial will compare Yanlishuang Buccal Dropping Pills with a matching placebo in 400 adults aged 18 to 65 years whose acute pharyngitis began within 48 hours and whose baseline throat-pain visual analog scale score is at least 4. Participants will be randomized 1:1 and treated under double-blind conditions. Each group will use four buccal dropping pills 4 to 6 times daily at intervals of at least 2 hours for up to 5 days. Participants whose sore throat resolves after at least 72 hours and remains absent for at least 24 hours may stop treatment early. The primary outcome is time to complete sore throat resolution. Secondary outcomes assess immediate pain relief, onset and resolution of pain, symptom and physical-sign response, complications, and work absence. Safety will be assessed using physical examinations, vital signs, laboratory tests, electrocardiograms, and adverse events.