Systematic Desensitisation: In relation to phobias, involves gradually desensitising the phobic person to the object of his/her fear, preferably in a relaxed setting or in a state of deep relaxation.. 

For example, in the case of arachnophobia (fear of spiders), the patient would first look at pictures of spiders, move on to look at spiders through glass at a distance, then close by until he/she can touch them and eventually cope with them running up and down their arm. 

Obviously, in the case of emetophobia, this is less practical since the fear is of an INTERNAL act and cannot be systematically confronted in the same way. The therapist could take steps to gradually induce varying degrees of nausea in the patient in the hope that this may lead to vomiting but it's not a method which can be suddenly halted at the patient's request - unlike confronting spiders. Alternatively, emetic drugs could be prescribed but there could be ethical implications with such a method. 

A UK Clinical Psychologist cannot prescribe an emetic drug and it is questionable whether inducing illness in a patient is ethical. One Gut Reaction member did try this approach. Further, actually confronting the phobia and vomiting (either voluntarily or otherwise) does not seem to reduce the fear of vomiting and can, in some cases, worsen the condition and can lead to future eating disorders or a fear of eating. Alternatively, watching Vomit Videos can be helpful in the systematic desensitisation of a patient who fears others vomiting. It is usually helpful to first watch these in reverse, fast-forward, with the sound switched off and then in colour with sound to gradually become used to them. It is important they are watched regularly until they fail to cause any anxiety or discomfort. For details of Vomit Videos available in the UK, go to vomit-videos

"A good website which I'm sure can support people suffering from emetophobia. A short remark: What you describe under "systematic desensitization" is actually "graded exposure with response prevention". Systematic  desensitization is a different behavioural method, and involves associating a feared stimuli with relaxation. The method was first developed by Joseph Wolpe in the late 1950īs".  - Feedback from Swedish Chartered Clinical Psychologist