Bonney's blue cystitis: a warning.

The instillation of diluted Bonney's blue into the bladder during gynaecological operations has been quite common practice over the last 50 years. Bonney's blue is composed of a 1:1 mixture of brilliant green and crystal violet dissolved in ethanol (90%) or industrial methylated spirit. Before insertion into the bladder this solution must be diluted with water to a 0.5% solution. Failure to do this will result in a severe inflammatory reaction within the bladder. The degree of resultant damage depends upon the duration of exposure. Persistent pain is a feature of this condition, although the other symptoms (frequency and urgency) may settle in time. Two cases of chemical cystitis resulting from the use of undiluted Bonney's blue are described to illustrate the possible consequences. Both patients were awarded 6-figure sums as compensation.