I've been researching neem oil. It seems to be beneficial in a varity of ways, besides critter control. It can be used skin issues, pain, and a bunch other ailments. Here's one for R.A.:
Rheumatism or Rheumatoid Arthritis is an autoimmune condition that can cause serious pain and inflammation. Modern medicine uses strong drugs like phenyl butazone and cortisone to relive the pain and inflammation of Rheumatism, however these drugs can cause many uncomfortable side effects. Clinical studies have conclusively demonstrated that the anti-inflammatory activities of various compounds in Neem leaves are equally as effective as phenyl butazone and cortisone.
In addition to relieving pain and inflammation the active constituents in Neem leaves are clinically proven to inhibit the prostaglandin mechanism, that causes pain, more effectively than aspirin. In the same study Neem significantly reduced acute paw edema as well. The consumption of Neem Leaf capsules and the topical application of slightly warmed Neem cream can help to alleviate the pain and inflammation of this condition.