In spite of the many recent reports on the damaging effects of LSD on human chromosome in vitro1,2 and in vivo3-6 and its ability to produce congenital malformations in rodents7, the teratogenic potential of this drug in humans is still uncertain. Two infants with limb malformations who had been exposed to LSD in utero have thus far been reported8,9. On the other hand, Cohen, et al.5, reported nine children and Hulten, et al.6, one child, all of whom had been exposed to LSD in utero and had no obvious birth defects although chromosome damage was apparent. Hecht and his co-workers9 have pointed out the need for additional data on infants who had in utero exposure to LSD, regardless of the presence or absence of congenital malformations, so that the teratogenic properties of the drug could be evaluated.