If you grew up in an Indian household, your grandparents must have handed you a spoonful of castor oil for just about everything. It was their cure-all. Turns out, they were not entirely wrong, at least when it comes to joint pain. Castor oil contains a compound called ricinoleic acid that is now being looked at for its potential to ease arthritis-related pain and inflammation. With more people turning to gentler, natural options alongside standard treatment, this old remedy is quietly making a comeback.What exactly is ricinoleic acid?Ricinoleic acid is a monounsaturated omega-9 fatty acid. It makes up around 90 per cent of castor oil’s composition and has been shown to have anti-inflammatory, analgesic, and antioxidant properties. In simple terms, it can help reduce swelling, ease pain, and possibly shield tissues from further damage.Why do people rub oil on sore joints?Topical use of castor oil is not new. Ayurvedic and folk traditions have long endorsed it for joint stiffness, swollen knees, and general aches. The practice usually involves warming the oil slightly, applying it generously over the affected area, and covering it with a warm cloth or compress.Heat improves circulation and opens up pores, which may help the ricinoleic acid penetrate deeper into the skin. Once inside, it is believed to interact with the body’s prostaglandin system, the same compounds that trigger inflammation and pain during arthritis flares.What does science say?Small animal studies have shown that ricinoleic acid can reduce swelling and pain in rodents with inflamed paws and joints.Human evidence is still a bit thin but not non-existent. A few small clinical trials suggest that castor oil packs may help reduce arthritis symptoms when used regularly. Reportedly, patients with knee osteoarthritis who used castor oil packs reported reduced pain and stiffness after four weeks. However, the sample size was small, and the study was not double-blind.Is it worth trying?If you are someone who is dealing with arthritis and over-the-counter painkillers are not helping you, castor oil could be a gentle, low-risk addition to your routine. However, it is worth noting that it is not going to reverse joint damage or magically un-stiffen your limbs overnight. What it might do is reduce the pain, especially if used regularly with warm compresses and gentle massage. Tips for trying castor oil at home:Buy cold-pressed, hexane-free castor oil. You want the pure stuff, not a chemical soup.Warm it slightly before applying. Use a hot water bottle or towel over the area for 20–30 minutes.Do a patch test before full use, especially if you have sensitive skin.Be consistent. Try it a few times a week for at least a month.Avoid broken skin or open wounds, since oil can trap bacteria.