Beta-agonists (beta 2) are the first treatment for acute asthma. Metered dose inhalers are preferable to nebulizers. During regular treatment, long-acting beta 2 show better results than sabutamol. Clinically relevant antiinflammatory activity has not been demonstrated. During regular treatment, tolerance to bronchodilator effects has not been detected but decrease of bronchoprotective effect is seen. These findings do not show clinical relevance. Short or long-acting beta 2 remain an appropriate and reliable treatment option for patients with asthma. Salmeterol and formoterol show similar action and adverse effects. The most rational treatment strategy seems to be: a) use inhaled steroids as the first and main regular treatment; b) when doses higher than 1,000-1,200 mcg/d of BCM or BUD are required, try long-acting beta-agonists; c) if that treatment is not effective enough, continue to increase inhaled steroid doses to identify patients responsive to higher doses.