Time magazine published an article in 1949 (12) entitled 
‘‘Milkweed,”’ in a section devoted to Medicine. It described 
some of Dr. Manuel Serrano’s experiments with ixbut in 
Guatemala: controlled testing of 1,800 women who had experi- 
enced trouble in nursing their babies indicated that 50% could 
not nurse at all without ixbut; 35% who could nurse only a little 
showed notable improvement after taking ixbut; while 15% did 
not benefit from ixbut. 
Dr. Serrano pointed out to Time that he was convinced that 
ixbut increased milk flow — actually milk, and not water. The 
active principle in ixbut that caused the increase in lactation 
had not been isolated in 1949. (Today, thirty years later, it still 
has not been determined just what this active principle may 
be.) Dr. Serrano in 1949 ruled out the milk-producing hormone 
prolactin: while prolactin did not enable his wife to nurse her 
four babies, ixbut did. 
Between 1949 and 1951, the late Dr. Efren C. del Pozo of 
Mexico City, former Secretary General of the Union de Uni- 
versidades de America Latina, carried out considerable re- 
search on ixbut in collaboration with Merck & Co., Inc., both 
in Mexico City and in Guatemala City (13). 
During 1949, Dr. del Pozo’s first testing was made at the 
Centro Materno Infantil Avila Camacho in Mexico City on 21 
nursing women. The ixbut plant material had been shipped by 
Air Cargo from Guatemala City and was thus from 4 to 7 days 
old. During 1950, Dr. del Pozo carried out further research at 
the Mexico City Penitentiary: 14 lactating mothers were tested: 
11 were given ixbut, while 3 were left as controls. In 1951, a 
third series of tests involving ixbut took place in Guatemala 
City under Dr. del Pozo’s direction, at the Maternidad de 
Guarderias Infantiles, on 22 nursing women and 3 non-lactating 
women. 
On the whole, the results of Dr. del Pozo’s experiments on 
the effect of ixbut were inconclusive and somewhat negative, 
even though in some nursing mothers a variable increase of 
lactation was noted following treatment with an aqueous 
extract of ixbut; average dose approximately 750 cc., a 10% 
infusion, daily for 25 days. 
