Vertigo is a severe case of dizziness, and it's usually caused when calcium crystals in the inner ear break loose. Doctors have tried a variety of techniques for treating it, and after years of study they've concluded that the simplest technique, known as the Epley manoeuvre, is the best.
In essence, you need to get the crystals from the ear canal and into the vestibule area of the ear where the crystals can be safely absorbed, and this is most easily done by gently twisting the patient's head. Start with the patient sitting upright, and gently twist his head 45 degrees towards the affected area. While keeping him in this position, lower him until he is lying on the table or floor, and gently extend the neck by 10 or 20 degrees, again depending on what is comfortable. Hold the position for 20 or 30 seconds.
Next, turn the head 90 degrees towards the unaffected area, and hold this position for a further 20 to 30 seconds.
Finally, turn the head a further 90 degrees towards the unaffected area by rolling the whole body and, again, hold for up to 30 seconds.
The patient should then sit up for another 30 seconds with the neck flexed - and the vertigo should have cleared.
(Source: Journal of the American Medical Association, 2008; 300: 157-8).