All soap contains sodium (bar) or potassium (liquid) hydroxide, which is lye. After the soap is made it is cured for 4-6 weeks during which a process called saponification takes place. This is a chemical process that naturally changes the oils and lye into soap. After this waiting period the oils are no longer oils (although the healing properties stay) and the lye is no longer lye and the soap is safe to use.