In humans, bitter herbs can stimulate the appetite, aid digestion, tone up the liver and kidneys, and derail a host of diseases. Bitter melon, in particular, has been shown in studies to have a remarkable capacity to lower blood sugar, owing partly to chemicals such as beta-sitosterol-d-glucoside and charantin; and to ease rheumatoid arthritis and systemic lupus erythematosus, because of immunosuppressive constituents such as alpha- and beta-momorcharin. Its phytochemicals, lanosterol and xeaxanthin, are considered to be cancer-preventive, and the saponin diosgenin...