diff --git a/nibabel/nicom/csareader.py b/nibabel/nicom/csareader.py
index 7327c53f72..8ca5a6d2d3 100644
--- a/nibabel/nicom/csareader.py
+++ b/nibabel/nicom/csareader.py
@@ -18,6 +18,8 @@
     'IS': int, # integer string
     }
 
+MAX_CSA_ITEMS = 199
+
 
 class CSAError(Exception):
     pass
@@ -116,7 +118,9 @@ def read(csa_str):
         # CSA1 specific length modifier
         if tag_no == 1:
             tag0_n_items = n_items
-        assert n_items < 100
+        if n_items > MAX_CSA_ITEMS:
+            raise CSAReadError('Expected <= {0} tags, got {1}'.format(
+                MAX_CSA_ITEMS, n_items))
         items = []
         for item_no in range(n_items):
             x0,x1,x2,x3 = up_str.unpack('4i')
diff --git a/nibabel/nicom/tests/data/csa_str_200n_items.bin b/nibabel/nicom/tests/data/csa_str_200n_items.bin
new file mode 100644
index 0000000000..780f196ffa
Binary files /dev/null and b/nibabel/nicom/tests/data/csa_str_200n_items.bin differ
diff --git a/nibabel/nicom/tests/data/csa_str_valid.bin b/nibabel/nicom/tests/data/csa_str_valid.bin
new file mode 100644
index 0000000000..6779d2c0f1
Binary files /dev/null and b/nibabel/nicom/tests/data/csa_str_valid.bin differ
diff --git a/nibabel/nicom/tests/test_csareader.py b/nibabel/nicom/tests/test_csareader.py
index b0d36a3d8b..2b93768c07 100644
--- a/nibabel/nicom/tests/test_csareader.py
+++ b/nibabel/nicom/tests/test_csareader.py
@@ -18,6 +18,8 @@
 CSA2_B0 = open(pjoin(IO_DATA_PATH, 'csa2_b0.bin'), 'rb').read()
 CSA2_B1000 = open(pjoin(IO_DATA_PATH, 'csa2_b1000.bin'), 'rb').read()
 CSA2_0len = gzip.open(pjoin(IO_DATA_PATH, 'csa2_zero_len.bin.gz'), 'rb').read()
+CSA_STR_valid = open(pjoin(IO_DATA_PATH, 'csa_str_valid.bin'), 'rb').read()
+CSA_STR_200n_items = open(pjoin(IO_DATA_PATH, 'csa_str_200n_items.bin'), 'rb').read()
 
 
 @dicom_test
@@ -65,6 +67,22 @@ def test_csa_len0():
     assert_equal(len(tags), 44)
 
 
+def test_csa_nitem():
+    # testing csa.read's ability to raise an error when n_items >= 200
+    assert_raises(csa.CSAReadError, csa.read, CSA_STR_200n_items)
+    # OK when < 200
+    csa_info = csa.read(CSA_STR_valid)
+    assert_equal(len(csa_info['tags']), 1)
+    # OK after changing module global
+    n_items_thresh = csa.MAX_CSA_ITEMS
+    try:
+        csa.MAX_CSA_ITEMS = 1000
+        csa_info = csa.read(CSA_STR_200n_items)
+        assert_equal(len(csa_info['tags']), 1)
+    finally:
+        csa.MAX_CSA_ITEMS = n_items_thresh
+
+
 def test_csa_params():
     for csa_str in (CSA2_B0, CSA2_B1000):
         csa_info = csa.read(csa_str)