Derivatives of 2(5H)-furanone (γ-crotonolactone) are important intermediate synthetic products with a wide range of biological effects that have become widely used in the pharmaceutical industry, medicine, and veterinary medicine, in particular in the prevention and treatment of fish diseases. However, the environmental issue of obtaining these compounds while reducing the negative impact on the surrounding environment remains relevant. This article describes for the first time a method of γ-crotonolactone synthesis that is based on the concept of green chemistry. Synthesis is carried out under mild conditions using nontoxic reagents by furfural oxidation. For the first time, a mixture of hydrogen peroxide and acetic acid was used for the oxidation of furfural in a ratio of 1:0.05. A mixture of organic acids (succinic, maleic, fumaric, formic, and cinnamic acids), obtained as a byproduct in the synthesis of γ-crotonolactone, can be used as a highly effective, ecofriendly organic fertilizer or in a preparation with a stimulating effect.