为了评价苯丙酮尿症（ＰＫＵ）饮食对患儿血清游离肉碱和酯化肉碱分布的影响，用放射同位素法对１９９３年１０月～１９９４年１２月间１５例饮食治疗组和１４例未治疗的对照组ＰＫＵ患儿进行了血清肉碱水平的测定。结果显示血清总肉碱水平（μｍｏｌ／Ｌ）治疗组为２４５５±５３２，对照组４５９５±７３７；游离肉碱水平治疗组为１８０７±５５８，对照组３０８４±５３９；酯化肉碱水平治疗组６９２±３４２，对照组１５１１±５５５。治疗组较对照组肉碱水平显著低下（Ｐ＜００１），但均没有肉碱缺乏的临床表现。认为含肉碱饮食的补充或提供含肉碱的ＰＫＵ强化奶粉可纠正患儿饮食治疗中外源肉碱的摄入受限。 In order to evaluate the effect of phenylketonuria (PKU) diet on the serum free carnitine and esterified carnitine in children, radioisotope method was used to evaluate the effect of PKU on the diet of 15 patients and 14 patients Serum carnitine levels were measured in the treated control group of PKU infants. The results showed that serum total carnitine level (μmol / L) treatment group 24  55 ± 5  32, control group 45  95 ± 7  37; free carnitine level treatment group was 18  07 ± 5  58, the control group 3084 ± 539, 692 ± 342 in the control group, and 1511 ± 555 in the control group. The treatment group than the control group carnitine levels were significantly lower (P <0  01), but no clinical manifestations of carnitine deficiency. Carnitine-based supplements or carnitine-containing PKU fortified milk are considered to correct limited intake of exogenous carnitine in children with dietary therapy.