Reply To: Hello, my five year daughter was found to be very deficient in vitamin d, so out pediatrician recommend a 600 iu supplement in addition to fish oil which has 500 iu and she was already taking a multivitamin with 400 iu. She has been on this dosage for about 2 months. She recently had severe vomiting with an increased heart rate and dilated pupils, we went to the e.r. and was told it was viral. At the time I did not think to mention her vitamin supplements, my wife later found out about vitamin d toxicity. Is she taking too much, she is about 34 lbs.