Active  Phyto-constituents varies  season to season as well as geographic region too. The consistency only  achieved by making Standardised Herbal Extract.  

I agree with Ajay. Different geographic locations have different environmental factors and stressors and thus plants tend to produce different compounds and secondary metabolites. You can be consistent if you outsource the plans from the same plantation. You can always try to isolate the bioactive compounds from herbal medicine to increase its efficacy. Sometimes crude extract can result to masking of bioactivity, several company unds masking the effect of bioactive compounds

Dear Gavali,

For consistency, try to get the herbal from the same place or region. They're tend to have the same environment, thus make them have similar metabolites. As for improving efficacy, you can put the herbal drug insides drug delivery system such as liposome etc.

Regards,

Didy

USING HERBAL COMBINATION

https://www.researchgate.net/publication/303999015_An_Update_Review_on_Polyherbal_Formulation_A_Global_Perspective

Article An Update Review on Polyherbal Formulation: A Global Perspective

Composition of phytoconstituents further varies between plant organs, dependent on daytime of harvest, and even annual specific factors like astral constellation might bee taken in account as we know from biodynamic agriculture. All together this indeed challanges consistency from a purely phytochemical point of view. Thus I agree with standardised extracts as solution for standardised processes in particular of industrial scale (dependent on the flexibility).

But concerning overall medical efficacy we might enlarge our windows of observation to more holistic scales.  Knowing that the same factors impact human metabolism as well, synergy might be the key towards a consistence. Not only of the drug product itself, but in convergence with individual therapeutical needs. According to the last comment this evaluation of synergy should consider plant-plant- or drug-drug-interaction but in particular the individual conversation of the drug on the consumer in agree with "personalised medicine". Thus a common extract or even direct application stays effective as alldays and can be pushed towards new limits by better understanding of physiological plant-to-human conversation.