This study aims is to evaluate, two hours after a single administration, the rate of sustained response produced by the association Geolab consisting of acetylsalicylic acid, sodium bicarbonate and anhydrous citric acid - oral powder, with the active comparator acetylsalicylic acid (Aspirin ® -- Bayer) - a simple tablet for the treatment of acute pain in patients with mild to moderate CTTE, using for both the visual analog scale pain - VAS.

The secondary objectives of the study are to evaluate:

• Modification of gastric pH after administration of drugs by measuring with gastroesophageal pH Monitor, comparing the results between the groups;
• The incidence of administration of rescue medications, through the accounts of patients and researchers, comparing the results between the groups;
• The percentage of improvement in time 30, 60, 90 and 120 minutes after administration, using the visual analog scale (VAS), comparing the results between the groups;
• Evaluate the gastric symptoms before and after treatment by clinical investigation of patients, comparing the results between the groups;
• Evaluate the change in associated symptoms (photophobia, phonophobia, nausea, vomiting), using 4-point scale (0 - absent 1 - mild 2 - moderate 3 - severe), comparing the results between the groups;
• Assess the quantitative and qualitative parameters related to adverse reactions, comparing the results between the groups.

Inclusion Criteria:

• Agreed to participate in the study expressed by signing the two copies of the informed consent and informed consent (IC) after approved by the IRB;
• Minimum age of 18 years;
• Clinical history of TTH, according to the criteria of the International Classification of Headache of the International Headache Society, in face of crisis.

Exclusion Criteria:

• Headache, migraine
• Chronic Tension-Type Headache (CTTH)
• Altered mental status
• Vital signs changed
• established or suspected pregnancy and lactation
• History of allergy to components of study drugs
• Current treatment with methotrexate
• Current treatment with Antinauseants
• Current treatment with anticoagulants such as heparin or coumarin-derivative
• gastric or duodenal disorders, chronic or recurrent active
• Liver and kidney disease severe
• Use of medications that have drug interactions with AAS