Adrenergic β-blockers are used to treat many conditions, including hypertension, cardiac arrhythmias, heart failure, angina pectoris, migraine, and tremors. The majority of the β-blockers including Propranolol, Metoprolol, Acebutolol, Alprenolol, Betaxolol, Carvedilol, Nebivolol and Oxprenolol are metabolised majorly by CYP2D6, and Bisoprolol is primarily metabolised by CYP3A4 enzymes. The drugs inhibiting or inducing them may alter the pharmacokinetics of those β-blockers. The plasma concentrations of Propranolol might be elevated by the concomitant use of drugs, such as SSRIs (Fluoxetine, Paroxetine), SNRIs (Duloxetine) and Cimetidine, while the plasma concentrations of Metoprolol increased by the concurrent use of SSRIs (Fluoxetine, Paroxetine), Amiodarone, Celecoxib, Cimetidine, Terbinafine, and Diphenhydramine. β-blockers can also interact pharmacodynamically with drugs, including fluoroquinolones, antidiabetic agents and NSAIDs. In addition, β-blockers may interact with herbs, such as curcumin, Ginkgo biloba, Schisandra chinensis, green tea, guggul, hawthorn, St. John’s wort and Yohimbine. This article focuses on clinically relevant drug interactions of β-blockers with commonly prescribed medications. In addition to Pharmacokinetics and Pharmacodynamics of the drug interactions, recommendations for clinical practice are highlighted. The prescribers and the pharmacists are needed to be aware of the drugs interacting with β-blockers to prevent possible adverse drug interactions.