有必要

yán gé de wèi shēng cuò shī hěn yǒu bì yào

严格的卫生措施很有必要。

Strict hygiene measures are necessary.

wèi què bǎo liáo xiào yǒu bì yào duō fú jǐ fù

为确保疗效，有必要多服几副。

It may be necessary to repeat the dose several times to effect a cure.