Limonene does not occur in large quantities in cannabis, it usually accounts for less than 2%. It is believed that the terpene may have potential therapeutic benefits, but not much is known about how it interacts with the brain and the body. The studies that have been carried out have focused on high dosages, far more than will be found in cannabis.
However, the studies have suggested that limonene may help to elevate mood, relieve stress, have antifungal properties, antibacterial properties, help to relieve heartburn and gastric reflux, and help to improve the absorption of other terpenes and chemicals through the skin, mucous membrane and digestive tract.
There has also been suggestions that limonene may have anti-tumour effects, specifically skin, mammary, lung and brain tumours. Nonetheless, far more research is needed before anything can be said definitively.