According to the doctrine of double effect, when an action can lead to two effects, one intended and desirable and the other unintended and undesirable, the unintended, undesirable effect is morally tolerable if .

The unintended, undesirable effect is morally tolerable if it brings a good result.

Explanation: The doctrine (or principle) of double effect is often invoked to explain the permissibility of an action that causes a serious harm.

According to the principle of double effect, sometimes it is permissible to cause a harm as a side effect (or “double effect”) of bringing about a good result even though it would not be permissible to cause such a harm as a means to bringing about the same good end.

if the action itself is not immoral

Explanation: When actions are not immoral i.e they followed the standard guidelines governing the society, the resultant effects of such action if not desired or not intended can be morally tolerable but if the actions were immoral then the unintended or undesirable effects will also not be morally tolerable or accepted. Although undesirable effects are not means to a desirable consequences.