#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?mx)(?:(\( (?: [^()]* | (?-1) )* \))|(\[ (?: [^][]* | (?-1) )* \]))(*SKIP)(*F)|\h*,\h*"
Local $sString = "Wheat Flour [Wheat Flour, Wheat Gluten, Calcium Carbonate, Iron, Niacin (B3), Thiamin (B1), Ascorbic Acid], Water, Yeast, Salt, Vegetable Oils (Palm, Rapeseed, oils (sunflower, rapeseed)), Soya Flour"
Local $sSubst = "\n"
Local $sResult = StringRegExpReplace($sString, $sRegex, $sSubst)
MsgBox($MB_SYSTEMMODAL, "Result", $sResult)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm