We report a case of intoxication resulting from the ingestion of a liquid, sold in the illicit market as "liquid ecstasy," which was found to contain 1,4-butanediol, a metabolic precursor of gamma-hydroxybutiric acid (GHB). Identification of the substance in the liquid was performed by gas chromatography-mass spectrometry (GC-MS). The toxicological analysis of blood, urine and gastric content of the victim was performed by immunoassay and gas chromatography with nitrogen-phosphorus detection as screening techniques and by means of GC-MS for confirmation and quantitation of 1,4-butanediol and GHB. The following drug concentrations were found: 82 microg/ml (blood), 401 microg/ml (urine) and 7.4 microg/ml (gastric content) for 1,4-butanediol and 103 microg/ml (blood), 430.0 microg/ml (urine) for GHB. In addition to these, other drugs detected and their blood concentration found in this case were methylenedioxymethylamphetamine (MDMA) 0.23 microg/ml and its metabolite methylenedioxyphenylamphetamine (MDA) 0.10 microg/ml. In the urine, a concentration of 0.10 microg/ml of benzoylecgonine was also found.