This presentation presents the precautionary principle in certain Common Law jurisdictions, namely, the UK, Australia, Canada, New Zealand, and the US, with emphasis on COVID-19. It can be observed that the precautionary principle primarily emerged in Common Law jurisdictions primarily from their own contexts or from the process of adjudication, reasoning, and logical extension and delineation out of practical needs. The precautionary principle is uncontroversially a general jurisprudential principle in the Common Law and commonalities across these jurisdictions concerning the matter can be found. The primary reason for this is the centrality of “reason”, “logic” and “abstract principle” in the construction of Common Law. Subtle variations among such jurisdictions can be observed. Most strikingly, the US’s libertarian and classical liberal precaution distances itself observably from the rest. Meanwhile, the NZ jurisprudence takes a more substantive approach in the course of judicial review than the rest. It also points to the vague distinction between prevention and precaution on account of the degree of uncertainty within the UK.