Overdosing medicine will certainly lead to serious illness.
It will certainly lead to serious illness to overdose medicine.
多くの薬を飲み過ぎると、かえって重大な病気にかかります。
単純に表現してみました。
多くの薬の飲みすぎ overdose medicine
(強い)推量 助動詞 will
~につながる lead to
確かに certainly
重大な病気 serious illness
Overdosing medicine will certainly lead to serious illness.
仮主語を使って、
It will certainly lead to serious illness to overdose medicine.
"If you take too many medicines, you could actually end up with a serious illness."
"If you take too many medicines, you could actually end up with a serious illness."
"Taking too much medication can actually lead to serious health problems."
"If you overuse medication, it can make things worse and even cause serious illness."
「多くの薬を飲み過ぎると」は、英語では take too much medication / overuse medication のように言うのが自然です。
日本語の「飲む」でも、英語は基本 take(薬を服用する)を使います。drink は使いません。