diff --git a/compile.go b/compile.go
index 5421a38..7d05781 100644
--- a/compile.go
+++ b/compile.go
@@ -812,18 +812,36 @@ func thompson(re []postfixNode) (Reg, error) {
 							// and them to the state's _content_. As mentioned above, if the exception has exceptions, then we can match
 							// those.
 							nodeExceptChars := slices.Concat(Map(node.except, func(node postfixNode) []rune {
-								return node.contents
+								nodeContents := node.contents
+								if caseInsensitive {
+									nodeContents = slices.Concat(Map(nodeContents, func(r rune) []rune {
+										return allCases(r, caseInsensitive)
+									})...)
+								}
+								return nodeContents
 							})...)
 							state.content = rune2Contents(nodeExceptChars)
 						} else {
-							state.except = append(state.except, node.contents...)
+							charsToAdd := node.contents
+							if caseInsensitive {
+								charsToAdd = slices.Concat(Map(charsToAdd, func(r rune) []rune {
+									return allCases(r, caseInsensitive)
+								})...)
+							}
+							state.except = append(state.except, charsToAdd...)
 						}
 					}
 				}
 			}
 			// Convert the current contents to []int, convert the result of rune2contents to []int, append then
 			// convert back to stateContents.
-			state.content = stateContents(append([]int(state.content), []int(rune2Contents(c.contents))...))
+			runesToAdd := c.contents
+			if caseInsensitive {
+				runesToAdd = slices.Concat(Map(runesToAdd, func(r rune) []rune {
+					return allCases(r, caseInsensitive)
+				})...)
+			}
+			state.content = stateContents(append([]int(state.content), []int(rune2Contents(runesToAdd))...))
 			state.output = make([]*State, 0)
 			state.output = append(state.output, &state)
 			state.isEmpty = false
@@ -935,7 +953,13 @@ func thompson(re []postfixNode) (Reg, error) {
 			// Map the list of nodes to a list of states, each state containing the contents of a specific node
 			states := Map(c.nodeContents, func(node postfixNode) *State {
 				s := newState()
-				s.content = rune2Contents(node.contents)
+				nodeContents := node.contents
+				if caseInsensitive {
+					nodeContents = slices.Concat(Map(nodeContents, func(r rune) []rune {
+						return allCases(r, caseInsensitive)
+					})...)
+				}
+				s.content = rune2Contents(nodeContents)
 				return &s
 			})
 			// Reduce the list of states down to a single state by alternating them