please share ur table structures.

Thanks for your reply, here are my tables:

users

Schema::create('users', function (Blueprint $table) {
        $table->increments('id');
        $table->string('name');
        $table->string('email')->unique();
        $table->string('password', 60);
        $table->rememberToken();
        $table->timestamps();
});

###patients

Schema::create('patients', function (Blueprint $table) {
        $table->increments('id');
        //Foreign key
        $table->integer('user_id')->unsigned();

        $table->string('ci')->unique();
        $table->string('name');
        $table->string('last_name');
        $table->string('gender');        
        $table->timestamps();
        $table->softDeletes();

        $table->foreign('user_id')
                 ->references('id')->on('users');
});

I should add that when I process a patient creation using tinker, the record is properly saved in the database. And it works as well when I fetch the user's patients as follows:

>>>$user = App\User::first();
>>>$user->patients()->get();
=> => Illuminate\Database\Eloquent\Collection {#677
     all: [
       App\Patient {#691
         id: "1",
         user_id: "1",
         ci: "123456789",
         name: "John",
         last_name: "Smith",
         gender: "Male"
         created_at: "2016-04-26 00:12:49",
         updated_at: "2016-04-26 00:12:49",
         deleted_at: null,
       },
     ],
   }

Hey @Veuge! Thank you very much! it was very helpful!!