8 
FMHS 
Hunt**’ 13 300 
Poisonous 
Aloes 
L.E. Newton 
Dept of Botany, Kenyatta U. 
Box 43844. Nairobi 
lnewton@avu.org 
A. ruspolkitui 
Many people, even outside the 
fraternity of succulent plant 
enthusiasts, have heart! of Aloe wm 
(sometimes referred to by the 
incorrect synonym A barbaric ns is). 
This species (probably better 
regarded as an ancient cultivar) is 
well known as a medicinal plant, anil 
there are numerous cosmetic and 
health products on the market that 
contain A cera extracts. Many other 
species of H/ocalso appear in lists 
of plants having medicinal value ( e g 
Watt & Breycr-Brandwljk. 1962; 
Drummond etai, 1975; Kokwaro, 
1993). in some cases forming the 
basis of a lucrative industry (Newton 
& Vaughan, 1996). The leaf exudates 
of aloes are especially useful for 
treating skin problems, such as 
radiation burns. 
What is not so well known, perhaps, 
is that there are also some pois« >nous 
species of Alov. In January 2001. on 
an expedition to Mandera District 
(North-Eastern Province. Kenya) 
witli Gilfrid Powys and Charlie 
W heeler, I collected specimens of an 
aloe plant that was said by the Itnul 
people to be used for killing hyaenas 
We were told that if the leaf extract 
is addeil to some meat that is left 
lying around at night, hyaenas will die 
soon after eating the meat. 
The plant is A rusftoHana, which Is a 
fairly w idespread species in Kenya 
and also occurs in Ethiopia and 
Somalia Lavranos (1995) cited a 
comment from a collector in Somalia 
that this species is used for poisoning 
hyaena Scbsebe and Gilbert ( 1997) 
stated that the leaves of A msfx/Uana 
smell strongly of mice A similar 
smell is characteristic of A. haltyi, 
which is also known as "the rat aloe” 
because of the smell (Reynolds. 
1966; Carter. 1994). 
It has been found that in these two 
Kenyan species, anil also in several 
other species in southern Africa. 
Madagascar and Arabia, this mouse 
or rat smell results from the presence 
of the toxic hemlock alkaloid g- 
conlceine (Dring etal., 198 ); Nash ct 
at .. 1992; Reynolds. 1997) Another 
Kenyan species with a similar smell 
is A data, presumably also 
containing g-coniceine. One 
Madagascan species has another 
poison, coniine (Dring el al.. 1984). 
