The research team concluded that, with such a small sample and no control group, they could not rule out a placebo effect – the patients believed they had improved symptoms as they were receiving ‘a treatment’. However, the scientists believe that local injections of botulinum toxin may indeed be effective for the type of resistant-to-treatment asthma associated with abnormal vocal cord movement. “Further mechanistic studies and a double-blind randomised controlled trial of botulinum toxin treatment are merited,” they write in their published paper.