The invention relates to the use of a composition comprising extract of Buddleja globosa Hope and pharmacologically accepted excipients for the preparation of a phyto-pharmaceutical agent, a drug or a nutraceutical for the prevention of gastrointestinal disorders, particularly those associated with treatment with nitrofurantoin or gastric disorders produced by ulcers, gastric diseases or damage to the gastrointestinal tract. The aforementioned disorders can correspond to abdominal pain, dyspepsia, nausea, vomiting, diarrhea, constipation, inflammation and cephalalgia resulting from treatment with nitrofurantoin and other antimicrobials. In addition, the extract and the compositions thereof can be used to enhance the antibacterial action of nitrofurantoin, particularly against Escherichia coli.