This cream was first developed in the 1980s and it wasn't till the 1990s that it was first made available for the treatment of sexually transmitted viruses where is was extremely successful. In the late 1990s it became available for the treatment of Basal Cell Carcinomas (BCCs). Before Aldara became available, sun damaged skin was often treated with Efudix. The key difference is that Aldara stimulates immunity within the skin while Efudix (being a chemotherapeutic drug) kills abnormally active cells (skin cancers) in the skin. Efudix has been used widely for over forty years and appears to be safe and effective predominantly because normal cells in the skin grow slowly and this seems to protect them from damage. Within skin our local immunity includes T cells that are part of our first line of defence. These cells are affected by the sun in such a way that they don't perform as the should and can be likened to them being a little sleepy. This results in abnormalities in the skin being allowed to grow to the point where we can see them and they can then become a threat to our health. Aldara (Imiquimod) switches on the immune system in the skin in the same way that you see when you have an infected laceration. This means that when Aldara is working on abnormal skin, the effect resembles an infected sore. This reaction is normal and is something we like to see. At the same time the immune system is also removing abnormalities within the skin that we cannot see. This inflammatory response does not need antibiotics.