The treatment of dyspepsia in the emergency department often consists of antacid in combination with viscous lidocaine, even though the specific etiology of the pain is frequently unknown. The efficacy of lidocaine as a component of symptomatic therapy was evaluated in a randomized, patient-blinded protocol. Patients presenting to the ED with dyspeptic symptoms were randomized to receive 30 mL of antacid (Mylanta II), or 30 mL of antacid plus 15 mL of 2% viscous lidocaine (GI cocktail). Patients recorded their pain score on an 11-cm linear analog scale prior to and 30 minutes after treatment. Seventy-six patients were enrolled; three were excluded from analysis due to incomplete data. Thirty-four patients were randomized to receive antacid and 39 to receive GI cocktail. Patients rated their baseline pain at 6.4 +/- 2.8 cm in the antacid group and 6.7 +/- 2.7 cm in the cocktail group (P greater than .50). Improvement in pain score with treatment was 0.9 +/- 2.9 cm in the antacid group compared with 4.0 +/- 3.4 cm in the GI cocktail group (P less than .0001). Assessment of pain relief using a five-point rating scale also indicated greater relief with GI cocktail therapy compared with antacid alone (P = .004). No adverse effects were noted with either treatment. We conclude that a single dose of antacid and viscous lidocaine provides a significantly greater degree of immediate pain relief than antacid alone in patients with dyspepsia.