To evaluate the effect of tea drinking on the occurrence of microcytic anemia in infants, we studied 122 healthy infants who underwent routine blood counts at the age of 6-12 months. An overall high frequency of anemia (Hb less than 11 gm/dl-48.4%), microcytosis (MCV less than 70 Mm3-21.3%) and microcytic anemia (19%) was found in the whole group. The percentage of tea drinking infants with microcytic anemia (32.6%) was significantly higher than that of the non-tea drinkers (3.5%). The daily amount of tea drinking was 50-750 ml (median 250 ml). The tea drinkers had significantly lower mean levels of hemoglobin than that of the non-tea drinkers (10.5 +/- 1.2 gm/dl vs 11.2 +/- 0.8 gm/dl, respectively) and significantly lower mean levels of mean corpuscular volume than that of the non-tea drinkers (71.5 +/- 7.1 micron 3 vs 76.1 +/- 4.6 micron 3). There were no significant differences between the two groups in their sex distribution and in the duration of breast feeding. The two groups differed with regard to their ages and social class but a multivariate analysis had excluded the possible confounding effect of these differences on the hematological results. Based on our finding we do not recommend giving tea to infants whose main source of iron is from milk, grains, vegetables or medicinal sources.