It could be easier for those with a fear of spiders to have a bath following a study published this week.
As long as this one doesn't come up the plughole
Researchers suggest arachnophobes, and people with other phobias, could be helped by a dose of the stress hormone cortisol, which impairs memory.
The University of Zurich team found giving the hormone before being exposed to the phobia trigger led to less fear.
But a psychiatrist said the Proceedings of the National Academy of Sciences study was not the whole answer.
Dr Cosmo Hallstrom, of the Royal College of Psychiatrists, said the treatment would not help people stop avoiding the thing they had a phobia of.
One common phobia therapy involves exposing a person to whatever it is they are frightened of in initially tiny doses, building up to full exposure - by say, holding a spider - so that they are no longer frightened and stop organising their life in a way that means they avoid the trigger of their phobia.
Others use psychological therapies to try and change the way people think about the thing they fear, without exposing them to it.
Cortisol impairs the retrieval of memories, so the principle the researchers were looking into was whether giving a dose of the hormone before people were exposed to a spider - or their own personal phobia trigger - would help.
The theory was tested on 40 people with social phobia and 20 with spider phobia.
Half of those studied were given cortisol and the rest a dummy version.
They were then either asked to give a speech in public, or exposed to a spider, depending on their phobia.
In both cases, subjects who received the hormone reported less stimulus-induced fear and anxiety.
Those who were frightened of spiders who were given the hormone treatment saw a progressive reduction of fear during each session over the two-week period of the study.
This was maintained during the final session when subjects received no drug treatment.
Those patients who were not given the hormone treatment who reported the least anxiety released the most cortisol, which the researchers say supports their theory.
The team, led by Dr Dominique de Quervain, suggest that cortisol treatment, in conjunction with behavioural therapy, could be used to reduce or even extinguish phobias and post-traumatic stress disorders which are triggered by a particular stimulus.
But Dr Hallstrom added: "It seems unlikely that you could remove a long-term phobia by simply altering the chemical levels of something that's already present in the body.
"This is very interesting research. But it is only part of the story.
"Phobias have two components. One is the fear of whatever it is you have a phobia about.
"But the other is that you spend your life avoiding that thing. This treatment wouldn't help with that."
Nicky Lidbetter, manager of the National Phobics Society, said all research into treatment possibilities was welcome, and this looked an interesting avenue to pursue.
But she added: "As phobias have a strong behavioural component ,we would see this particular treatment as something that could be used to complement other psychological interventions such as cognitive behavioural therapy."