An apparatus for extracting components from a solid (e.g. extracting natural products from plant material). The material used is placed in a thimble made of thick filter paper and this is held in a specially designed reflex condenser with a suitable solvent. The chamber holding the thimble fills with warm solvent and this is led back to the source via a side arm. The apparatus can be operated for long periods, with components concentrating in the source vessel. It is named after Franz Soxhlet, who devised it in 1879.