A biodegradable lubricant for greasing chainsaw chains and guides. A biodegradable fluid specially formulated to meet the stringent requirements of lubricating chainsaw chains and guides. It is able to extend their service life, while safeguarding the environment. Based on plant oils specially treated for oxidation resistance and a biodegradable adhesion agent, enabling the lubricant to maintain its hold on the equipment despite the application of gravitational forces (vertical run-off) and centrifugal forces (rapid rotation). Furthermore, these plant oils possess a very high lubricating power, and prevent direct metal-on-metal contact which would generate rapid wear.