Plant and animal-derived products are crucial components in complementary and alternative medicine. Although modern medicine has provided numerous innovations and advancements, these often fail to reveal new and dependable, inexpensive treatments nor real cures that are relatively free of adverse side effects. We present evidence that hirudotherapy, which utilizes leeches, improves certain diseases, including osteoarthritis. Osteoarthritis, a disease in joints, could benefit from use of medicinal peptides found in leech saliva, components of its immune system.