diff --git a/src/ntru_poly.c b/src/ntru_poly.c
index 03b0371..a5386ce 100644
--- a/src/ntru_poly.c
+++ b/src/ntru_poly.c
@@ -352,6 +352,9 @@ poly_inverse_poly_q(fmpz_poly_t Fq,
 				goto cleanup;
 		}
 
+		if (fmpz_poly_is_zero(g) == 1)
+			goto cleanup;
+
 		if (fmpz_poly_degree(f) == 0)
 			break;
 
@@ -464,6 +467,9 @@ poly_inverse_poly_p(fmpz_poly_t Fp,
 				goto cleanup;
 		}
 
+		if (fmpz_poly_is_zero(g) == 1)
+			goto cleanup;
+
 		if (fmpz_poly_degree(f) == 0)
 			break;