The present disclosure provides methods for obtaining gaultherin, a natural salicylate derivative, from plant tissue. The methods involve preventing the hydrolysis of the gaultherin in the plant tissue by disrupting the plant tissue under solvent conditions lacking a drying agent. The disclosure further provides various forms of plant-derived gaultherin, including alcoholic extracts, aqueous solutions and dried preparations, all suitable for use as a natural aspirin substitute. Moreover, the disclosure provides methods of using gaultherin-containing compositions to increase serum salicylic acid, to treat cancer cells, to treat cardiovascular (e.g., cardiopulmonary) conditions, to treat anti-inflammatory responses, and to inhibit cyclooxygenase.