Statins, as seen on TV (Lipitor, Crestor, Zocor, etc.) Some types of statins are naturally occurring, and can be found in such foods as oyster mushrooms and red yeast rice. I am taking some mushroom juice. It is yummy. You're not supposed to eat any grapefruit, but I'm wildly allergic to it anyway.
Side effects are cognitive loss, neuropathy, pancreatic and hepatic dysfunction, and sexual dysfunction, renal damage, muscle deterioration, and nerve damage. These are all pretty rare, though, and since these are literally the most popular drugs on the market, lots of people are using them.
One medicine which keeps your intestines from absorbing fat. Instinctively, this seems like a good idea, but IT CAUSES CANCER. No dice.
Niacin, yup, the vitamin, which -- good to get some, but better not to induce liver toxicity!
Medicines which make your liver produce more bile. Instinctively, I think that anything *else* that touches the liver is not good.