Background: The common cold is a common and frequent respiratory disease mainly caused by viral infection of the upper respiratory tract. Chinese herbal medicine has been increasingly prescribed to treat the common cold; however, there is a lack of evidence to support the wide utility of this regimen. This protocol describes an ongoing phase II randomized controlled clinical trial, based on the theory of traditional Chinese medicine (TCM), with the objective of evaluating the efficacy and safety of Lian-Ju-Gan-Mao capsules (LJGMC), a Chinese patent medicine, compared with placebo in patients suffering from the common cold with wind-heat syndrome (CCWHS). Methods/design: This is a multicenter, randomized, double-blind, placebo-controlled phase II clinical trial. A total of 240 patients will be recruited and randomly assigned to a high-dose group, medium-dose group, low-dose group, and placebo-matched group in a 1: 1: 1: 1 ratio. The treatment course is 3 consecutive days, with a 5-day follow-up. The primary outcome is time to all symptoms' clearance. Secondary outcomes include time to the disappearance of primary symptoms and each secondary symptom, time to fever relief, time to fever clearance, and change in TCM symptom and sign scores. Discussion: This trial is a well-designed study according to principles and regulations issued by the China Food and Drug Administration (CFDA). The results will provide high-quality evidence on the efficacy and safety of LJGMC in treating CCWHS and help to optimize the dose for the next phase III clinical trial. Moreover, the protocol presents a detailed and practical methodology for future clinical trials of drugs developed based on TCM.