Can we follow always the proverb "No risk no gain"?

Philosophically, I would say "yes."  But from a strictly business perspective I would say "no."  With proper forethought, risk can definitely be minimized and often averted completely.

It is not a proverb. it is a theory by an Economist John Maynard Keynes. It also says "More the risk you take more the profit you make". 

It depends on the logical and practicality of the risk. If the risk exceeds the limit then its better to move out.

I say we should take calculated risk depending on the situation.

YES we can.. but it should be a CALCULATED Risk!