In current study, anti-parasitic properties of Nicotiana tabacum  leaves (N. tabacum L.) and their traditional use in ethno-veterinary therapy were investigated using both in-vitro and in-vivo approaches. Crude aqueous extracts (CAE) of N. tabacum L. were used to evaluate in-vitro antiparasitic effect of Haemonchus (H.) placei that had been directly retrieved from the abomasum of cows. The nematodes' death or paralysis within three hours subsequent to being exposed to different quantities 25, 50 and 100 mg/ml of CAE proved to be statistically significant (P<0.05) indicator. Cattle infected with gastrointestinal nematodes, specifically H. placei, were orally administered with crude aqueous extracts (CAE) and crude methanolic extracts (CME) at gradually higher dosage of 1.0 and 3.0 gm/kg, respectively to evaluate in-vivo anthelmintic efficiency. When administered with 3.0 gm/kg of the body weight, CME showed an ideal decrease of 75.8 and 79.03% parasitic infection but CAE showed 48.88 and 51.11% reduction after 5 and 10 days of treatment, respectively (P<0.05). The overall reduction in eggs per gram was 98.68% in positive controls treated with levamisole HCl. Being an initial investigation of its kind in Pakistan, the outcomes suggested that N. tabacum L. have potential to be used as anti-parasitic agent in ethno-veterinary medication.