diff --git a/ethermess.c b/ethermess.c
index 0656e89..fe305e2 100644
--- a/ethermess.c
+++ b/ethermess.c
@@ -200,6 +200,9 @@ intmax_t saturating_sub(intmax_t a, intmax_t b) {
 intmax_t saturating_mul(intmax_t a, intmax_t b) {
 	// Doesn't give 100% right results when one parameter is INTMAX_MIN,
 	// but at least it won't ever overflow
+	if (a == 0 || b == 0) {
+		return 0;
+	}
 	if (a < 0) {
 		return saturating_sub(0, saturating_mul(saturating_sub(0, a), b));
 	}