In this critical review, we explore the study design, strengths, and limitations of landmark trial “Anticholinergic therapy vs. onabotulinumtoxinA for urgency urinary incontinence”. This trial was the first to directly compare two key treatment options for urge urinary incontinence – anticholinergic medication and intravesical botox, and still influences clinical guidelines a decade after publication. This non-inferiority, double-blinded, multi-centre randomised controlled trial administered Solifenacin or intra-detrusor botox to women, measuring outcomes six months post-treatment. Non-inferiority of the treatments was established, though Botox had a higher rate of retention and infection, with side effect profile rising as the key discriminator in selecting first-line therapy.