diff --git a/src/lib/services/toaster.service.ts b/src/lib/services/toaster.service.ts
index 33d7814..03d6f55 100644
--- a/src/lib/services/toaster.service.ts
+++ b/src/lib/services/toaster.service.ts
@@ -95,9 +95,9 @@ export class Toaster {
         }
     }
 
-    private _sanitizeParams(params: Record<string, string | number>): Record<string, string | null> {
+    private _sanitizeParams(params: Record<string, string | number | undefined>): Record<string, string | null> {
         return Object.entries(params).reduce((acc, [key, value]) => {
-            acc[key] = stripHtml(value.toString()).result;
+            acc[key] = stripHtml(value?.toString() ?? '').result;
             return acc;
         }, {} as Record<string, string | null>);
     }