diff --git a/netfilterqueue/_impl.pxd b/netfilterqueue/_impl.pxd
index d11aea8..35b6a45 100644
--- a/netfilterqueue/_impl.pxd
+++ b/netfilterqueue/_impl.pxd
@@ -141,7 +141,7 @@ cdef extern from "libnetfilter_queue/libnetfilter_queue.h":
 
     int nfq_fd(nfq_handle *h)
     nfqnl_msg_packet_hdr *nfq_get_msg_packet_hdr(nfq_data *nfad)
-    int nfq_get_payload(nfq_data *nfad, char **data)
+    int nfq_get_payload(nfq_data *nfad, unsigned char **data)
     int nfq_get_timestamp(nfq_data *nfad, timeval *tv)
     nfqnl_msg_packet_hw *nfq_get_packet_hw(nfq_data *nfad)
     int nfq_get_nfmark (nfq_data *nfad)