Some similarities between Jainism and Buddhism include their comparable behavioral proscriptions for liberation and their shared historical origin in the 6th century BC. Both were also founded by men who rejected a life of luxury for one of asceticism and the pursuit of truth.
Specifically, the founder of Jainism was a man called Vardhamana, whose family was rich and influential. At 30 years old, he gave away all of his possessions and, following an extended period of contemplation, became enlightened.
Siddhartha Gautama, the founder of Buddhism, likewise renounced his worldly possessions and status to determine the cause of suffering, eventually becoming the enlightened Buddha.
Both the Jainist and Buddhist traditions stress non-attachment and an honest, honorable life as a path to enlightenment. Jains, however, are somewhat more extreme in their emphasis on non-violence, or "ahimsa," extending sincere consideration to all living organisms, including insects, plants and even bacteria. As a result, Jains refrain from consuming not only meat and dairy products, but any food or beverage that causes unnecessary harm to microorganisms or insects, including root vegetables, honey, fermented foods, mushrooms and fungi, alcohol and unfiltered water.
Perhaps owing to their restrictive lifestyle, another key difference between Jainism and Buddhism is that, while the latter has spread around the world, Jainism has remained relatively localized to its birthplace of India.