Guaifenesin or glyceryl guaiacolate is an aromatic organic compound. It has two benzene rings in its structure with a methyl group attached at the ortho position of the ring through an ester linkage and two glycerol groups attached at the meta position. It is available without a prescription and is taken orally. Its main beneficial effect is that of an expectorant in acute respiratory diseases. It helps in bringing up phlegm form the respiratory tract. Its expectorant effect is attributed to its quality of thinning and increasing the volume of secretions in the respiratory tract. It also increases the excretion of uric acid from the blood serum and urine and can be used in the treatment of gout and fibromyalgia. It also provides relief in asthma and coughing. It can also thin the mucus in the birth canal and facilitate conception.