Microbicides to protect women from HIV are urgently needed. Several potential pharmaceutical microbicides are now undergoing obligatory clinical trials to check safety, acceptability and efficacy before approval for use. Microbicides may have side-effects and, paradoxically, their use may increase the risk of acquiring HIV. Several widely available substances have been suggested as microbicides, including substances with a low pH such as lemon juice, vinegar, soft drinks and lactobacillus dairy products. Because of the potential for harm it is important that these substances are tested before their use is widely promoted. After small scale safety and acceptability studies, their promotion needs to be evaluated as a communication intervention.