> The researchers next conducted a randomized, double-blind clinical trial in 45 individuals with arachnophobia. Fifteen received 40 mg of propranolol after spending 2 minutes in proximity to a large tarantula, 15 got placebo, and another 15 received propranolol without exposure to a tarantula. One week later, all patients who received propranolol with spider exposure were able to approach and actually pet the tarantula.