Oral rehydration solutions and electrolyte content of water.

exhibit two peaks; one at 265 nm, consistent with DNA absorption, and the second at 450 nm. Bilirubin absorbs maximally between 420 to 480 nm-the blue range. Despite such evidence, few clinically adverse side effects have been reported. Ennever et al3 found the most effective wavelength for the production of 4Z 15E bilirubin to be 390 nm with an overall effective band from 350 to 470 nm. But other types of isomerisation occur and the relative contributions of different isomerisations to the overall effect of phototherapy is unknown. Vecchi et al' have shown that longer wavelengths in the green range result in more effective phototherapy than daylight lamps. They note that the depth of penetration of light in human skin increases with increasing wavelengths. Clinical indications for phototherapy remain confused. Obviously infants should be exposed to the minimal necessary irradiation. Until optimal conditions are defined, however, we can only reiterate our plea that paediatricians measure the 'dose' of phototherapy and that manufacturers provide emission spectra for phototherapy light sources.