Castor oil contains many beneficial components, including fatty acids, flavonoids, phenolic compounds, amino acids, terpenoids and phytosterols. These various compounds give the oil the following properties and potential health benefits: 
Anti-diabetic
Anti-inflammatory
Antimicrobial
Antioxidant
Hepatoprotective (ability to prevent damage to the liver)
Free radical scavenging
Wound-healing
The oil and other parts of the castor plant have been used to treat: 
Abdominal disorders
Arthritis
Backache
Constipation
Muscle aches
Parasitic infections
Chronic headaches
Gallbladder pain
PMS 
Rheumatism
Sleep problems like insomnia