"unforeseen side effects" is correct and usable in written English.
You can use it to refer to negative consequences that occur unexpectedly as a result of an action or process. For example, "The new medication did help with pain, but it also caused some unforeseen side effects such as nausea and drowsiness."
"The benefits are still unproven and with any product designed to have an effect on human health, there could also be unforeseen side effects".
Implementing this simple board governance device likely costs less than instituting new formal regulatory disclosure requirements, which can impose unforeseen side effects.
But Lilly executives are conservative when discussing the company's prospects because, as Lilly learned to its dismay, unforeseen side effects can wipe out even the most promising drugs.
The implication is that a new pill, despite its unforeseen side effects, is necessary to cure the sexual malaise that appears to have sunk over the country.
There is always a small risk of unforeseen side effects, but it pales next to the harm done by influenza every year — and the harm it could do in the future if we have an inadequate supply of vaccine.
The reason clinicians test drugs with randomized trials is to establish whether the hoped-for benefits are real and, if so, whether there are unforeseen side effects that may outweigh the benefits.
Vice-President Cheney touts the Bush Doctrine as being responsible for the Arab Spring, but I believe it was an unforeseen side effect.
The drugs successfully block tissue growth that could impede blood flow, but can have the unforeseen side effect of increasing the risk of blood clots and heart attacks.
I'm a little appalled at all the time I've lost, but then, wasting time wasn't exactly an unforeseen side effect; it was part of the fun.
One unforeseen side effect of giving up the passport would be his future avoidance of the taxes levied, wherever they live, on all US citizens … Ah, I see where that has brought us.
Results Although the planned enrollment was 135 patients, the study was halted after only 71 patients had been randomized because of the unforeseen side effect of leg pain, which occurred almost exclusively in patients with terbogrel treatment.
