Traditionally, in the Southern Asian countries, Psidium cattleyanum is a widely used plant for the management of various ailments such as gastrointestinal, respiratory, and cardiac disorders, but it lacks proof on a scientific basis, and therefore, this is the major emphasis of the current research work. Crude extract of Psidium cattleyanum (Pc.Cr) was preliminary analyzed for the presence of different classes of bioactive molecules. The aqueous and dichloromethane fractions of Pc.Cr were subjected to in vitro and in vivo studies. It was applied at variable concentrations (0.1–10 mg/ml) to isolated rabbit jejunum to investigate spasmolytic effect. Concentration dependent curves of calcium were constructed to check the calcium channel antagonistic activity. For the evaluation of tracheorelaxant activity, isolated tracheal tissue was treated with High-K+ (80 mM) and carbachol (CCh) and then challenged cumulatively with Pc.Cr. To study the antidiarrheal effect of the plant extract, castor oil-induced diarrhea model was adopted. For evaluation of the hypotensive effect of Pc.Cr, it was given intravenously to preanesthetized normotensive rats, and the response was recorded using pressure transducer. Platelet rich plasma was used for the assessment of the antiplatelet activity when challenged with purinergic and adrenergic agonists. Concentration-dependent inhibition of spontaneous and High-K+ mediated contractions in isolated jejunum was observed by the application of Pc.Cr. Contractions induced in isolated tracheal tissue by High-K+ and CCh were inhibited by application of Pc.Cr to these tissues. Similarly, application of Pc.Cr to High-K+ and phenylephrine (PE) treated aortic strips resulted in vasodilation. Platelet aggregation inhibition was shown by Pc.Cr against adenosine diphosphate (ADP) only. The antidiarrheal effect was observed as a reduction in the total number of feces in Pc.Cr-treated mice when given castor oil. Dose-dependent hypotension was seen in normotensive rats when treated with Pc.Cr intravenously. This study showed the spasmolytic, tracheorelaxant, vasodilator, platelet aggregation inhibitory, antidiarrheal, and hypotensive activities of P. cattleyanum which may be due to the blockage of calcium channels, but the involvement of any other pathway cannot be ignored.