A warning device for issuing a warning concerning the end of a fluid drip when said fluid (Fi) is contained in a flexible-walled pouch (Po) having an outlet tube (Tus) and that is in an inflated shape when it is full of said fluid and in a flat shape when it is at least partially empty, the device being characterized in that it comprises: · a base; · two tabs (11, 12); · means for mounting a second one of the two tabs (11, 12) in co-operation with said base; · means for mounting the first one of the two tabs (11, 12) to pivot relative to said base about a first pivot axis (21, 22) situated in the proximity of a first end (11-1, 12-1) the first tab, said first pivot axis being substantially parallel to the plane containing said second tab and being situated at a distance from said second tab that is greater than the thickness of the pouch (Po) when it is in its flattened shape (Pfa), said first tab being mounted to pivot about the first axis (21, 22) so as to be suitable for occupying all positions between a first position and a second position, the first position (P1-1, P2-1) being that in which its second end (11-2, 12-2) remote form its first end (11-1, 12-1) is at a distance from the second tab that is not less than the value of the thickness of said pouch (Po) in its inflated shape (Pfg), the second position (P1-2, P2-2) being that in which its second end (11-2, 12-2) is at a distance from the second tab that is substantially equal to the value of the thickness of said pouch in its flattened shape (Pfa); · means for delivering a "threshold" signal when the distance between the second end (11-2, 12-2) of the first tab and the second tab reaches a determined minimum value; and · means for delivering an alarm signal (Sa) as a function of said threshold signal. · a base; · two tabs (11, 12); · means for mounting a second one of the two tabs (11, 12) in co-operation with said base; · means for mounting the first one of the two tabs (11, 12) to pivot relative to said base about a first pivot axis (21, 22) situated in the proximity of a first end (11-1, 12-1) the first tab, said first pivot axis being substantially parallel to the plane containing said second tab and being situated at a distance from said second tab that is greater than the thickness of the pouch (Po) when it is in its flattened shape (Pfa), said first tab being mounted to pivot about the first axis (21, 22) so as to be suitable for occupying all positions between a first position and a second position, the first position (P1-1, P2-1) being that in which its second end (11-2, 12-2) remote form its first end (11-1, 12-1) is at a distance from the second tab that is not less than the value of the thickness of said pouch (Po) in its inflated shape (Pfg), the second position (P1-2, P2-2) being that in which its second end (11-2, 12-2) is at a distance from the second tab that is substantially equal to the value of the thickness of said pouch in its flattened shape (Pfa); · means for delivering a "threshold" signal when the distance between the second end (11-2, 12-2) of the first tab and the second tab reaches a determined minimum value; and · means for delivering an alarm signal (Sa) as a function of said threshold signal.