Presence of air microbes such as bacteria is reported to be associated with a number of illnesses. Chemical based cleaning products and fumigants available in the market have their limitations and sometimes pose severe ill effects on health of mankind.  In order to explore the potential of weeds as bio-fumigant to reduce microflora in indoors, experiments were conducted with the fumes of three weeds namely purple fleabean Vernonia cinerea (Compositae), coat buttons Tridax procumbens (Asteraceae), Lantana camara (Verbenaceae) and oleo-gum resin of guggul  Commiphora wightii (Burseraceae), an important ingredient of Yajnya ‘Havan samigri’ (composition of different herbal ingredients). The study revealed significant reduction in bacterial colonies (cfu/15 m) after fumigation in Petri-plates exposed to the air. Per cent reduction of bacterial count over control (before fumigation) was recorded as 79.7, 83.7, 67.3 and 82.3% and 76.7, 80.7, 61.0 and 77.3% by V. cinerea, T. procumbens, L.camara and C. wightii after 24 and 48 hours, respectively. The findings of the present study highlights that these weeds can be utilized as an ingredient in preparation of herbal fumigants for cleaning the indoors.