Mechamism: completely unknown! I'm uncomfortable with this. But a lot of people find them useful.

Treat: cholecystitis (inflammation of the gall bladder), poor eliminations, epilepsy (for which they were almost a specific), various liver conditions such as cirrhosis and torpid liver, and scleroderma; and also for headaches, appendicitis, arthritis, incoordination between assimilations and eliminations, colitis, intestinal disorders such as stricture and colon impaction, incoordination between nervous systems, neuritis, and toxemia.

• Cayce Herbal Remedy 5734: Abdominal Castor Oil Pack — indications above are from here
• Placement
• Castor Oil Packs — directions