The oesophageal transit of six commonly used tablets and capsules containing barium sulphate was evaluated radiologically using fluoroscopy in 121 healthy volunteers. To determine the influence of the subject's position and the amount of water taken each subject swallowed three preparations while recumbent and standing and with 25 ml or 100 ml of water. Failure of swallowing (defined as oesophageal transit taking more than 90 seconds) occurred in 22% of 726 swallowings, but globus was complained of in only 33% of these. Sixty per cent of the volunteers had difficulty in taking one or more of the preparations. Many preparations adhered to the oesophageal membrane and started to disintegrate in the lower part of oesophagus. It is recommended that subjects should remain standing for at least 90 seconds after taking capsules or tablets and that all preparations should be taken with at least 100 ml of water. Small tablets are swallowed most easily. Liquid forms of medication (suspensions) should be considered for bedridden patients and those who have difficulty in swallowing.