In industrialized countries, data on antituberculosis treatment are scanty. The aim of this study was to describe the tuberculosis (TB) treatment programme from diagnosis to drug intake in a model area of northern Italy, evaluating: 1) antiTB regimens prescribed and their adequacy; 2) dosage of drugs; 3) side-effects; and 4) drug resistance. Individual data on new TB cases from all the existing health facilities of the area were collected by means or a prospective surveillance system based on the systematic review of original clinical forms. Regimens were classified as adequate, potentially adequate and inadequate, based on published recommendations. Data on drug dosage, side effects and drug resistance were analysed. Out of 109 TB cases with regimen recorded on clinical records, 20.2% included more than four major drugs, 63.3% three drugs and 16.5% two drugs. The regimens were classified as 1.8% adequate, 85% potentially inadequate and 12.8% inadequate. The dosages prescribed (mean +/- SD in mg.kg body weight-1.day-1) were: isoniazid: 6.8 +/- 2.7: rifampicin: 10.2 +/- 2.5; ethambutol: 21.3 +/- 4.5; streptomycin: 17.4 +/- 4.0: and pyrazinamide: 15.2. Twelve per cent of cases required treatment modification due to side-effects. Resistance to one single drug was found in 9% of cases, but no case with multidrug-resistant TB. The description of the treatment programme revealed that: 1) the majority of regimens are potentially adequate; 2) they are at a proper dosage; 3) the side-effects are in agreement with the literature; and 4) drug-resistance rates are low.