Quality control methods for

Maximum limit of pesticide residues for medicinal plant materials 
The toxicological evaluation of pesticide residues in medicinal plant materials 
should be based on the likely intake of the material by patients. In general, the 
intake of residues from medicinal plant materials should account for no more 
than 1% of total intake from all sources, including food and drinking-water. 
Certain plant materials may contain extremely high levels of pesticide residues, 
but the levels remaining after extraction are usually much lower, because of the 
low solubility in water or ethanol. It is therefore important to determine the 
actual quantity of residues consumed in the final dosage form. 
Where the nature of the pesticide to which the plant material has been exposed 
is unknown, it is sufficient to determine the content of total chlorine and to base 
the calculation on the acceptable residue level (ARL) of the most toxic chlorine-
containing pesticide (e.g. aldrin or dieldrin). 
An ARL (in mg of pesticide per kg of plant material) can be calculated on the 
basis of the maximum acceptable daily intake of the pesticide for humans (ADI), 
as, recommended by FAO and WHO, and the mean daily intake (MDI) of the 
medicinal plant material. 
Some countries have established national requirements for residue limits in 
plant materials. Where such requirements do not exist, the following formula 
may be used: 
x100
MDI
60
x 
E
x 
ADI
ARL
=

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Quality control methods for medicinal plant materials 
where
ADI = maximum acceptable daily intake of pesticide (mg/kg of
body weight); 
E = extraction factor, which determines the transition rate of the
pesticide from the plant material into the dosage form; 
MDI = mean daily intake of medicinal plant product. 
The 60 in the numerator represents mean adult body weight, while the 
denominator incorporates a consumption factor of 100 reflecting the fact that no 
more than 1% of the total pesticide residue consumed should be derived from 
medicinal plant material. 
This formula is based on the acceptable daily intake (ADI) determined by FAO 
and WHO.