The concept of probiotics now has been around for more than a century, with its consumption increasing exponentially; owing to exciting scientific and clinical findings, limiting side effects of existing pharmaceutical agents and increased consumer demand for natural products. But, the evidence for their safety and efficacy has largely been anecdotal, lacking an integrated scientific basis. Clinical studies conducted with probiotics were of inadequate design and resulted in unreliable data. That is the reason why despite having innumerable potential therapeutic uses probiotics are not being universally accepted. The purpose of present article is to amalgamate various branches of research which would help in development of “better”, “commercial” and “pharmaceutical” probiotic products with defined strength, mechanism of action and indication. Probiotics have been classified into oral and vaginal in accordance to their route of administration, describing the health benefits. The article summarizes the research on significance of strain selection, interactions with coadministered agents and appropriate clinical studies uncovering the safety issues. There is a special emphasis on pharmaceutical issues including probiotic delivery systems, technological challenges during formulation, regulatory concerns, quality control and market potential. Developments in the techniques for in vitro evaluation have also been discussed.