D-limonene is derived from the peels of citrus fruits. It showed anti-inflammatory, wound healing and anticancer effects in laboratory studies. D-limonene was shown to alter the signaling pathways within cancer cells in a way that stops cancer cells from multiplying and causes their death (this is called "apoptosis"). In animal models, D-limonene slowed the growth of pancreatic, stomach, colon, skin, and liver cancers. It also slowed formation of tumors and their progression in animals exposed to cancer-causing substances. However, these anticancer effects have not been shown in humans.