<p>This study evaluated the effects of pediatric iron- and multivitamin-containing syrups on the color stability and translucency of Invisalign First aligners and assessed the effectiveness of different cleaning protocols in reducing discoloration. Ninety-six specimens were divided into three solution groups (artificial saliva, iron syrup, and multivitamin syrup) and four cleaning subgroups (no cleaning, toothbrushing, cleaning tablets, and combined cleaning). The samples were immersed in the test solutions for 1 min daily, followed by the assigned cleaning protocols, for one week. Color coordinates (L*, a*, b*) were measured using a spectrophotometer at baseline and after immersion, and color (ΔE₀₀) and translucency (ΔRTP₀₀) changes were calculated. Data were analyzed using generalized linear models (<i>p</i> &lt; 0.05). Both solution type and cleaning protocol significantly affected color (<i>p</i> &lt; 0.001), with iron syrup causing the greatest discoloration (ΔE₀₀: 6.48 ± 1.87). Combined cleaning resulted in the lowest color change values. Translucency was also significantly reduced (<i>p</i> &lt; 0.001), particularly in the iron syrup group (ΔRTP₀₀: − 5.89 ± 2.31). Pediatric syrups, especially iron-containing formulations, caused clinically perceptible discoloration and reduced translucency in clear aligners. Combined cleaning reduced discoloration, but measurable changes remained. Clinicians should advise removing aligners during syrup intake and maintaining appropriate cleaning routines to preserve aesthetics.</p>