Spasticity following upper motor neuron lesion can be alleviated by few treatments such as physiotherapy, drugs and neurosurgery. However, they all have side effects, limitations or lack of selectivity. We tentatively used the paralyzing effects of botulinum toxin. Since the late 1970's the use of this toxin has increased and it has been extended to numerous muscles and diseases of various causes. In this pilot and open study we use botulinum toxin in spasticity. Eight patients (7 stroke, 1 head injury) with longstanding severe spasticity (minimum: 12 months, maximum: 15 years) were included. Spasticity greatly interfered with their activity in daily life and was resistant to oral antispastic medications. Six patients suffered from pain and 4 had cutaneous lesions especially maceration of the palm of the hand. A-botulinum toxin was injected with a 30-gauged needle. The sites chosen for injection were the following muscles: biceps brachii, brachioradialis, flexor digitorum, flexor carpi, tibialis anterior, flexor digitorum longus. Altogether 41 injections were performed. There were no side effects. Spasticity was improved in all patients. Five patients reported significant pain relief on a visual analogical scale. Most of them reported a benefit in their limb tone and referred to subjective improvement in the activity of daily life and nursing. The beneficial effects of one injection lasted more than 5 months. Seven patients received a second course of treatment. A double-blind study of botulinum toxin in spasticity is to be undertaken to assess its effectiveness and safety when prescribed in the required dose to treat this condition.